Our primary objective for this project is the development of a sensitive radioimmunoassay for the detection of soluble human melanoma tumor associated antigens (TAA). Purified TAA and antisera specific for these TAA are required. We have produced a battery of human anti-melanoma alloantisera and non-human primate antisera which, once suitably absorbed, are operationally monospecific for human melanoma TAA. Using these antisera to monitor for pronase-solubilized melanoma TAA, we have performed preliminary purifications of these TAA from other cell membrane constituents such as HLA and Dr antigens and B-2 microglobulin. We plan to continue purification of these TAA using antibody and lectin binding techniques. Once purified melanoma TAA are obtained, they will be employed as antigen standards in the RIA and used to immunize mice. Spleen cells from these immunized mice will then be used to produce momnoclonal anti-melanoma TAA antibody-secreting hybridomas. In addition, we are attempting to produce hybridomas between murine myeloma cells and B-enriched lymph node cells from a chimpanzee which has been hyperimmunized against human melanoma. Useful monoclonal antibodies from these two sources will be used in the RIA and to assist in further large-scale TAA purifications. We will evaluate the usefulness of the RIA for detection of serum-borne melanoma TAA in melanoma patients. The RIA will be of potentially great benefit in three ways: 1) using the RIA we may be able to detect recurrent tumor growth in melanoma patients prior to its clinical manifestations, 2) the RIA could be used to monitor the response of melanoma patients to various therapeutic modalities, and 3) the RIA could be used for basic studies into the role of soluble TAA, free or in the form of immune complexes, on the host:tumor interaction.